test(lua/environment): add missing tests

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

src/bindings/lua/environment.cpp

@@ -50,6 +50,11 @@ static int mk_environment(lua_State * L) {
     return push_environment(L, f.get_environment());
 }
 
+static int environment_mk_child(lua_State * L) {
+    rw_environment env(L, 1);
+    return push_environment(L, env->mk_child());
+}
+
 static int environment_has_parent(lua_State * L) {
     ro_environment env(L, 1);
     lua_pushboolean(L, env->has_parent());
@@ -214,6 +219,7 @@ static int environment_tostring(lua_State * L) {
 static const struct luaL_Reg environment_m[] = {
     {"__gc",           environment_gc}, // never throws
     {"__tostring",     safe_function<environment_tostring>},
+    {"mk_child",       safe_function<environment_mk_child>},
     {"has_parent",     safe_function<environment_has_parent>},
     {"has_children",   safe_function<environment_has_children>},
     {"parent",         safe_function<environment_parent>},

tests/lua/env4.lua

@@ -0,0 +1,30 @@
+assert(not pcall(function() get_environment() end))
+local env = environment()
+env:add_uvar("Z", level(level("M"), 1))
+assert(env:is_ge(level("Z"), level("M")))
+local child = env:mk_child()
+assert(env:has_children())
+assert(child:has_parent())
+child:add_var("x", Const("Int"))
+for o in child:local_objects() do
+   assert(o:get_name() == name("x"))
+   print(o)
+end
+local eenv = empty_environment()
+assert(eenv:find_object("Int"):is_null())
+assert(not pcall(function() env:parent() end))
+local p = child:parent()
+assert(p:has_children())
+assert(not pcall(function() env:add_uvar("Z") end))
+child:add_definition("val1", Const("true"), true)
+child:add_definition("val2", Const("Bool"), Const("true"), true)
+local ok, msg = pcall(function() child:add_definition("val3", Const("Int"), Const("true"), true) end)
+assert(not ok)
+print(msg)
+assert(child:normalize(Const("val2")) == Const("val2"))
+child:add_theorem("Th1", Eq(iVal(0), iVal(0)), Const("Trivial"))
+child:add_axiom("H1", Eq(Const("x"), iVal(0)))
+assert(child:has_object("H1"))
+local ctx = context(context(), "x", Const("Int"), iVal(10))
+assert(child:normalize(Var(0), ctx) == iVal(10))
+assert(child:check_type(Var(0), ctx) == Const("Int"))